1. Field of the Invention
This invention relates generally to valves. More particularly, the invention relates to valves having multiple ports.
2. Description of Related Art
Valve assemblies having multiple ports have existed for many years and have been used in a wide variety of applications. One such application is the use in dental medicine. A device known as a tooth de-scaler is used to remove plaque build-up on teeth. The device uses ultrasonic waves to effectuate the plaque removal.
While the device is being used, a stream of fluid is drawn into a small hose attached to the tip of the de-scaling device where the fluid exits. The fluid is used to wash away any loosened plaque. Such tooth de-scaling devices are designed to allow for three different fluid options. One option is regular tap water. A second option is bi-carbonate water. A third option is fluoride-fortified water.
Selection of the fluid source is accomplished by a multi-port valve which is required to handle pressures of approximately 65 psi which is a typical pressure at which tooth de-scaling devices are operated. The need to be able to shift quickly from one fluid option to another poses a number of problems.
One problem relates to the leakage of air from the multi-port valve. This is a problem that is common to most multi-port valves. The key is to limit the leakage to less than one bubble per second to achieve what is known as xe2x80x9cBubble tightxe2x80x9d operation when the valve ports are plugged and the valve is submerged and pressurized. Some designs, for example, a conical valve and conical valve seat design, do not sufficiently seal to minimize bubble production. As a result, an undesirable hissing sound emanates from such a valve assembly when exposed to fluid pressures in the 65 psi range.
It is therefore an object of the invention to provide a multi-port valve system that can minimize air leakage to no more than one bubble per second. Another object of the invention is to provide a valve having a xe2x80x9cminiature envelopexe2x80x9d which meets or exceeds the criteria to receive UL approval.
A still further object of the invention is to provide a bearing system that allows for effortless, maintenance-free rotation of the valve rotor within the valve housing.
The invention described herein employs a unique ball bearing support system for a multi-port valve assembly. The valve apparatus also employs slipper seals to provide a virtually air-tight seal between a rotor and stator of the assembly so that a multitude of fluids can be selectively transported through the valve in an efficient cost effective manner.
The rotor/stem assembly is supported by ball bearings situated in annular chases provided in the valve housing and in a top end of the rotor. Bores provided in the rotor receive the slipper seals which have through apertures to connect apertures in the rotor in fluid communication with apertures in the stator. Axial compression springs set within the rotor bores and within bores established in the slipper seals enhance the sealing effect by applying axial force to the slipper seals, forcing them into contact with the sealing face of the stator.
By rotating the rotor, a specific aperture in the stator is aligned with a fluid transmittal aperture/seal in the rotor. This aperture is in fluid communication with central fluid delivery apertures in the rotor and stator via a transverse channel. Alignment is accomplished by a system of detents and detent channels positioned to allow for alignment of the rotor apertures to the stator apertures. Stator apertures not aligned with the fluid receiving aperture are aligned with other apertures in the rotor to provide a means to rapidly depressurize lines that are either not in use or were in use just prior to the line presently selected. A vent bore situated in a side wall of the housing provides egress for any pressure buildup in unused lines.
The ball bearing support system coupled with the slipper seals provides a durable multi-port valve that can supply a selected fluid without compromising the integrity of the seals or ease with which the fluid lines can be selected for delivery of the desired fluid. These and other objects and features of the present invention will be apparent from a review of the drawings and a reading of the following detailed description of the invention.